CVE-2026-41428: Budibase: Authentication Bypass via Unanchored Regex in Public Endpoint Matcher , Unauthenticated Access to Protected Endpoints

CVE-2026-41428 · Severity: critical · CVSS 9.1 · Published 2026-04-24

Budibase is a low-code platform for building and deploying internal tools and workflows. An unauthenticated attacker can bypass authentication on protected API endpoints by appending a public endpoint path as a query parameter, gaining access to sensitive user data including full user directory listings, account holder information, and the ability to trigger system actions. This exposure affects any public Budibase instance accessible over the internet.

Technologies: Budibase, @budibase/backend-core (npm). Vendors: Budibase, npm.

Quick answers

Is CVE-2026-41428 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-41428 being exploited in the wild.
How severe is CVE-2026-41428?
Critical severity, with a CVSS score of 9.1, published 24 April 2026.
Which products and versions are affected?
@budibase/backend-core (npm) <= 3.35.3, SEMVER:introduced=0,last_affected=3.35.3.
Is there a fix for CVE-2026-41428?
A patch was published on 2026-04-16: version 3.35.4 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-41428 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-41428?
Check whether you run Budibase or @budibase/backend-core (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is a regex-based authentication bypass in the endpoint matcher middleware. The authenticated middleware compiles public endpoint patterns into unanchored regular expressions (no ^ or $ anchors) and tests them against the full request URL including query string. An attacker can append a public endpoint path as a query parameter (e.g., /api/global/users/search?x=/api/system/status) causing the regex to match in the query string portion, falsely marking the request as public and skipping authentication. The vulnerability affects only endpoints that lack secondary per-route authentication middleware; endpoints on builderOrAdminRoutes and adminRoutes are protected by independent middleware checks. Fixed in version 3.35.4 by anchoring regex patterns and/or using ctx.request.path instead of ctx.request.url.

Affected products

  • Budibase Budibase all versions before 3.35.4

Identifiers

  • CVE-2026-41428
  • GHSA-8783-3wgf-jggf

Timeline

  • 2026-04-16: disclosed
  • 2026-04-16: patched: version 3.35.4 released

References

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